Die mechanism



M. H. NIELSEN IE MECHANISM April 13, 1954 VENTO Jed Patented Apr. 13,1954 DIE MECHANISM Moritz H. Nielsen, Chicago, Ill., assignor toIllinois Tool Works, Chicago, 111., a corporation of IllinoisApplication November 5,1948, Serial No. 58,415

4 Claims.

This invention relates generally to means for and methods of producingblanks from fiat stock, and more particularly to blanking dies and tomethods of producing blanks having smooth accurately formed peripheralsurfaces.

It is well known to those skilled in the art of employing die mechanismsthat difiiculties have been experienced from the presence of fins orrough margins formed during the blanking operation. In conventionalstamping or blanking operations there is ever present the tendency forthe material adjacent the blank periphery to be drawn axially, so as topresent the above mentioned uneven edge or fin. This is particularlytrue in drawing sheet metal. In drawing sheet metal there is everpresent the tendency to form a chamfered or beveled edge along theadvancing margin of the blank opposite from the above mentioned fin.Also, considerable diiiiculty has been experienced in forming blanksfrom nonmetallic sheets such as molded fibrous materials, due to thetendency for such material to tear along the blank periphery during thepunching operation. Because of the aforesaid difliculties such blanksare not suitable to be used where accurate peripheral dimensions andsurface smoothness are essential. It is important, for example, ifaccurate gear teeth are to be formed in the periphery of a blank thatthe marginal dimensions of the blank be held within close tolerances andthat the peripheral surface contour be free from any irregularities. Itis therefore an important object of the present invention to providemeans in the form of a die mechanism which will overcome the abovementioned and other disadvantages heretofore experienced. To this end,the invention contemplates a simple and extremely practical devicewhereby blanks conforming with predetermined dimensional and surfacecontour standards may be produced successively from a strip of sheetmaterial.

More specifically, the invention contemplates apparatus and methodswhereby disks may be blanked successively from sheet material at a givenstation, each blank as it is severed from the sheet stock serving toadvance previously formed blanks into operative association with aseries of peripheral cutting teeth.

It is a further object of the present invention to avoid subjection ofthe above mentioned fiat stock to any tearing or crushing during theblank-v ing operation, and to this end it contemplates successiveremoval of limited peripheral areas of the blank stock resulting in theultimate presentation of a blank having the required peripheralcharacteristics.

With the view of producing blanks having the desired marginal orperipheral characteristics referred to above, the present inventioncontemplates subjection of a disk stamped from fiat stock to successiveremoval of limited circumferential areas of peripheral stock, suchcircumferential areas being also very limited in depth so as to avoidany tendency for the stock .to be pulled axially, torn, or crushed.

It is another object of the present invention to provide apparatus andmethods for producing blanks of the type referred to above, whereby chipremoval is greatly facilitated, and to this end it is contemplated toemploy relatively large openings positioned externally of and adjacentto the cutting zone, which openings readily will permit ejection ofchips and thereby positively preclude jamming or clogging.

The foregoing and other objects or advantages will be apparent from thefollowing detailed description when considered in connection with theaccompanying drawings wherein:

Fig. 1 is a central vertical sectional view of a die mechanism which isrepresentative of one embodiment of the invention.

Fig. 2 is a plan sectional view of the device shown in Fig. 1, said viewbeing taken ,alongthe line 22 of Fig. 1 which is coincident with theplane of the upper surface of the fiat stock.

Fig. 3 is a transverse sectional view taken substantially along the line3-3 of Fig. 1.

Fig. 4 is a perspective view illustrating a blank having a roughenedperipheral surface.

Fig. 5 discloses the blank after it has been trimmed so as to present anaccurate smooth peripheral surface.

Fig. 6 is a perspective view of .a die used inthe mechanism shown inFigs. 1 to 3 inclusive, said die being made up of a plurality ofsuperimposed die sections.

Fig. '7 is a central vertical sectional view of the die illustrated inFig. 6.

Fig. 8 is a horizontal sectional view of the die taken along the line8-8 of Fig. '7; and

Figs. 9 to 13 inclusive are fragmentary sectional views taken alongvarious locations in the die to illustrate successive steps of roughtrimming, finish trimming and final finishing operation in theproduction of a blank having a very accurate and smooth periphery.

Referring now to the drawing more in detail wherein like numerals havebeen employed to designate similar parts throughout the various figures,it will be seen that the present invention contemplates a die mechanismdesignated generally by the numeral [4 in Figs. 1 to 3 inclusive.

. shoulders.

This die mechanism includes the usual base or bed it which supports adie block or plate 18. A strip of sheet stock 20 may be fed across thetop surface of the plate i8 as illustrated in Figs. 1 to 3 inclusive.Above the work strip 20 is a punch block 22 which on its under sidecarries a punch holding plate 24. Below the plate 24 i a combinedstripper and cutting plate 26 which is normally urged downwardly fromthe block 22 by suitable heavy duty coil springs 23.

The work strip 20 is fed step by step from the right side of the diemechanism l4 as viewed in Fig. 1. As the advancing end of the strip 20is first moved into position, the punch block and parts carried therebyoccupies its uppermost position so as to permit clearance between thelower extremity of a blanking punch 36 and a complementary die bushing32 mounted within the die plate !8. Movement of the strip at this pointis arrested, and subsequent downward movement of the punch causes anaperture 34 to be formed. After the subsequent upward movement of thepunch 39 the work is advanced to its next position with the previouslyformed aperture 3 coming to rest immediately beneath and in registrationwith a locating pin 36. Subsequent downward movement of the punch movesthe locating pin 36 into the previously formed aperture 34 and the punch30 again blanks an aperture in the work. After the above mentioned finaloperation has again been repeated, the Work is advanced into positionbeneath a blanking punch 38 and above a die structure designatedgenerally by the numeral 40. This die structure and the operationsperformed by it are best illustrated in Figs. 6 to 13 inclusive.

As the work strip 20 reaches its position beneath the punch 38 and abovethe die structure so, the punch block 22 descends, first bringing intocontact with the work strip opposed shoulders d2 of a punch bushing 44best illustrated in Fig. 3. The contact of the punch bushing 4 3 withthe work occurs before contact of the punch 38 with the work but after alocating pin 46 within the punch 38 moves into registration with thepreviously formed aperture 34. Continued downward movement of the punchblock 22 and plate 25 after the punch bushing 44 has been moved intoengagement with the upper surface of the work strip 28 causes increasedcompression of the coil springs 28. The pressure exerted during thisperiod of the cycle is sufiicient to cause the shoulders 42 to becomeembedded within opposite margins of the stock. The stock is notcompletely sheared but is gripped on opposite sides by these Note therecesses 4211 on the opposite sides of the work piece in Fig. 2 whichare formed by the shoulders 42.

The purpose of initially engaging opposite margins of the work strip 20by the shoulders 42 is to hold the material of the Work stock firmly inposition while the punch 38 acts upon the sheet stock. That is to say,the shoulders 42 support opposite sides of the work and thus counteractany tendency for the work to bulge or tear during the blanking operationof the punch 38. This enables very narrow stock to be employed, thusreducing resulting scrap to a minimum.

After the shoulders 42 of the punch bushing 44 have firmly gripped theopposite margins of the work strip 28 so as to form the recesses 42a,continued downward movement of the punch block 22 brings the punch 38into operative association with the work strip. This causes an annulus'38 to be rough blanked from the strip stock 20.

This annulus or blank member 43 is illustrated in Fig. 4. In performingthis rough blanking operation the punch 38 coacts with a die plate 55forming the uppermost element of the die structure 48. This die plate 58is provided with a central aperture 52 which cooperates with the punch38. An initial stamping or blanking operation, such as that performed bythe coaction of the punch 38 and the die plate 58 results in a ratherrough peripheral surface and diameter dimensions not conforming withrequired standards of accuracy. Hence the blank must be subjected tofurther peripheral treatment.

As the work strip is again indexed or shifted a second blank is punchedfrom the stock by the punch 38 and complementary die plate 55, and thiblank serves to force the previously formed blank through the nextadjacent die plate 5 This die plate 54 is provided withcircumferentially spaced internal teeth 56 designed to perform aroughing trimming operation upon the blank periphery.

In Fig. 9 a fragmentary horizontal sectional view is taken transverselyof the die plate 56 looking downwardly. Thus the blank 13 is within theopening 52 of the die plate 56 and immediately beneath the blank will beseen the peripheral teeth 56 of the next adjacent die plate 54. In Fig.10, which constitutes a similar sectional view taken transversely of theplate 54 it will be seen that the teeth 56 of the die plate 54 haveremoved limited circumferentially spaced areas of relatively small depthfrom the periphery of the blank 48. Immediately beneath the blank willbe seen in dotted lines the teeth 53 of the next adjacent die plate 68.Fig. 11 constitutes a section taken transversely of the die plate 62. Itwill be seen that the die plate 89 again trims the peripheral stock,leaving only small projecting portions 62. In Fig. 11 die teeth 64 ofthe next adjacent die plate 66 will be seen in dotted positionimmediately beneath the blank. Fig. 12 is a section taken transverselyof the die plate 68 showing the teeth 64 thereof removing limitedcircumferentially spaced areas of peripheral. stock. The periphery ofthe blank has now been reduced in diameter and presents plurality ofperipheral projections 58. In Fig. 12 the teeth 63 of the next adjacentdie plate '10 are shown in dotted lines. As the blank is forced throughthe die plate 10 as shown in Fig. 13 the teeth 68 remove all but smallperipheral projections 12. As the die is finally forced through the lastdie member 74 at the bottom of the structure 40, the small peripheralprojections 72 are sheared off as the blank is forced through the dieopening Hi.

It will be apparent from the foregoing description of the die structure#10 that the die plates thereof function to first rough blank an annulusfrom the strip stock within the die .plate 50 and then rough trim theperiphery of this blank between the die plates Stand 50. This roughtrimming consists in the successive removal of limited circumferentialareas of stock. This initial rough trimming cuts away the surfaceroughness resulting from the initial blanking operation but furthertrimming is necessary in order ultimately to produce a blank having therequired degree of surface smoothness and accuracy. Hence the twosubsequent die plates 66 and 19 perform the final trimming by againremoving circumierentially spaced limited areas of peripheral stock. Thelast die plate Hi which is provided with an aperture 16 defined by -asmooth accurately dimensioned wall performs the finishing operationwhich consists in removing the small peripheral projections left fromthe previous trimming operation, and at the same time lapping orburnishing the surface of the blank so as to produce the desiredperipheral surface characteristics.

It will be noted that the die plates of the die structure 40 are stackedone upon the other and held together by suitable dowels 18. It will alsobe seen that the adjoining surfaces of adjacent dies are provided withradial recesses or openings 80 which in plan partake the shape of across (see Fig. 8). These recesses or passageways 80 become largertoward their outer extremity as clearly illustrated in Figs. 3 and 7.The purpose of the recesses or passageways 80 is to facilitate thedisposition of chips formed during the trimming operations. Thesepassageways are sufficiently large to accommodate all of the chips asthey are formed during each downward stroke of the punch block 22, andtheir disposition is such as to enable displacement of accumulated chipsby directing a blast of air through the passageways from any suitablesource as, for example, from the conduit 82 shown in Fig. 3. Theintroduction of kerosene vapor through the air conducting passagewaysalso serves a very useful function. The vapor provides sufficientlubrication to facilitate the punching operation and the compressed airblows away the chips that are directed to the passageways 80. It will beseen from Fig. 3 that a chamber 84 is provided within the die block [8to receive the blast of compressed air, preferably mixed with kerosenevapor from the conduit 82. The chips are blown across the die structure40 and emerge at the open side of the chamber 84 to the left of Fig. 3.

It will be apparent from the foregoing description that the presentinvention contemplates improved apparatus and methods whereby accuratelydimensioned blanks may be produced. By first rough trimming andthereafter finish trimming the blank periphery, it is in condition to belapped or burnished by the final die section or plate. Also, by havingthe shaper teeth of certain of the die sections arranged in staggeredrelation with respect to the teeth in the next adjacent section,peripheral areas of limited cross-section at space intervals may beremoved without subjecting the material of the blank to deleteriousstrains and stresses. The functioning of the shaper teeth of each diesection or plate is such that the blank periphery is properly trimmedbefore being subjected to the final burnishing operation. By having theradially disposed arrangement of chip accommodating passageways, theremoval of chips from the area adjacent the shaper teeth is greatlyfacilitated. As previously pointed out, the introduction of compressedair further enhances the ease with which chip disposal may beaccomplished. The use of a lubricating vapor, such as kerosene vaporintroduced through the air conducting passageways, .provides sufiicientlubrication to facilitate the punching and trimming operations. It willalso be apparent that the die mechanism contemplated by the presentinvention is easily assembled and disassembled and constitutes a minimumnumber of constituent parts. Hence the present invention provides veryeconomical least two adjacent plate-like die sections having internaland circumferentially spaced shaper teeth disposed entirely around theinner periphery thereof and of limited and the same radial extent, eachtooth extending the axial length of its associated die section, theteeth of one said die section being peripherally staggered with respectto the teeth on the adjacent die section for successively removing fromthe blank single peripherally spaced sections of the same depth by eachtooth with the sections removed by the teeth of one die sectionconstituting substantially the entire remainder of material left betweenpreviously removed sections, and a finishing die section having a smoothinternal periphery for removing any residual minute projections from theblank and burnishing the same.

2. Die mechanism as claimed in claim 1, wherein the die sectionsimmediately adjacent the finishing die section have the teeth thereofprojecting inwardly to a slightly greater extent than the teeth of themore remote die sections.

3. Die mechanism as claimed in claim 1, wherein chip removal passagesare provided between each of the die sections.

4. Die mechanism as claimed in claim 1, wherein the die sections areprovided with offset corner sections serving to space apart adjacent diesections to provide chip removal passages communicating with the shaperteeth.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 262,375 Cosgrove Aug. 8, 1882 772,841 Smith Oct. 18, 19041,295,957 Blanchard Mar. 4, 1919 1,361,568 Donaldson Dec. 7, 19201,731,117 Warren Oct. 8, 1929 1,944,246 Langhammer Jan. 23, 19342,102,071 I-Iart Dec. 14, 1937 2,153,909 Baker Apr. 11, 1939 2,194,595Hart Mar. 26, 1940 2,237,959 Hansen et al Apr. 8, 1941 2,250,392 PhaneufJuly 22, 1941 2,304,185 Lee Dec. 8, 1942 2,348,064 Gebhardt May 2, 19442,355,451 Lindberg Aug. 8, 1944 2,392,172 Markstrum Jan. 1, 19462,392,823 LePointe Jan. 15, 1946 2,473,815 Oakley June 21, 19492,490,029 Clawson Dec. 6, 1949 2,525,098 Hougland Oct. 10, 1950 FOREIGNPATENTS Number Country Date 9,438 Great Britain June 28, 1915

